Enum Description to String

Question

I have the following ENUM:

[Flags]
public enum DataFiat {

  [Description("Público")]
  Public = 1,

  [Description("Filiado")]
  Listed = 2,

  [Description("Cliente")]
  Client = 4

} // DataFiat

And I created an extension to get an Enum attribute:

public static T GetAttribute<T>(this Enum value) where T : Attribute {

  T attribute;
  MemberInfo info = value.GetType().GetMember(value.ToString()).FirstOrDefault();
  if (info != null) {
    attribute = (T)info.GetCustomAttributes(typeof(T), false).FirstOrDefault();
    return attribute;
  }
  return null;
}

This works for non Flags Enums ... But when I have:

var x = DataFiat.Public | DataFiat.Listed;
var y = x.GetAttribute<Description>();

The value of y is null ...

I would like to get "Público, Filiado, Cliente" ... Just as ToString() works.

How can I change my extension to make this work?

Thank You

[Break the flags down into the individual values](http://stackoverflow.com/questions/4171140/iterate-over-values-in-flags-enum), get the attribute for each individual value and build up a string of them all. — Adam Houldsworth, Feb 19 '14 at 14:34
But it wouldn't work here since your extension method returns only 1 value, however what you want to do is to return a list of values. Otherwise the extension method would need to have the knowledge how to combine those attributes — peter, Feb 19 '14 at 14:35
This is not going to localise very nicely if you will want english speakers to use it. — Gusdor, Feb 19 '14 at 14:40

score 2 · Accepted Answer · edited May 23 '17 at 10:31

You can use this:

var values = x.ToString()
             .Split(new[] { ", " }, StringSplitOptions.None)
             .Select(v => (DataFiat)Enum.Parse(typeof(DataFiat), v));

To get the individual values. Then get the attribute values of them.

Something like this:

var y2 = values.GetAttributes<DescriptionAttribute, DataFiat>();

public static T[] GetAttributes<T, T2>(this IEnumerable<T2> values) where T : Attribute
{
    List<T> ts =new List<T>();

    foreach (T2 value in values)
    {
        T attribute;
        MemberInfo info = value.GetType().GetMember(value.ToString()).FirstOrDefault();
        if (info != null)
        {
            attribute = (T)info.GetCustomAttributes(typeof(T), false).FirstOrDefault();
            ts.Add(attribute);
        }
    }

    return ts.ToArray();
}

That was an option ... But I would like to replicate what ToString() does to a Flags enum ... It returns the strings separated by comma — Miguel Moura, Feb 19 '14 at 14:38

score 1 · Answer 2 · answered Jul 19 '19 at 07:17

in .NET CORE without any additional libraries you can do:

 public enum Divisions
 {
    [Display(Name = "My Title 1")]
    None,
    [Display(Name = "My Title 2")]
    First,
 }

and to get the title:

using System.ComponentModel.DataAnnotations
using System.Reflection

string title = enumValue.GetType()?.GetMember(enumValue.ToString())?[0]?.GetCustomAttribute<DisplayAttribute>()?.Name;

score 0 · Answer 3 · answered Feb 19 '14 at 14:39

I think you want to make something like that

using System;

public enum ArrivalStatus { Unknown=-3, Late=-1, OnTime=0, Early=1 };

public class Example
{
   public static void Main()
   {
      int[] values = { -3, -1, 0, 1, 5, Int32.MaxValue };
      foreach (var value in values)
      {
         ArrivalStatus status;
         if (Enum.IsDefined(typeof(ArrivalStatus), value))
            status = (ArrivalStatus) value;
         else
            status = ArrivalStatus.Unknown;
         Console.WriteLine("Converted {0:N0} to {1}", value, status);
      }
   }
}
// The example displays the following output:
//       Converted -3 to Unknown
//       Converted -1 to Late
//       Converted 0 to OnTime
//       Converted 1 to Early
//       Converted 5 to Unknown
//       Converted 2,147,483,647 to Unknown

score 0 · Answer 4 · answered Feb 19 '14 at 15:01

using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;

public static class Program
{
[Flags]
public enum DataFiat
{

  [Description("Público")]
  Public = 1,

  [Description("Filiado")]
  Listed = 2,

  [Description("Cliente")]
  Client = 4

} 

public static ICollection<string> GetAttribute<T>(this Enum value)
{
  var result = new Collection<string>();
  var type = typeof(DataFiat);

  foreach (var value1 in Enum.GetValues(type))
  {
    var memInfo = type.GetMember(value1.ToString());
    var attributes = memInfo[0].GetCustomAttributes(typeof(DescriptionAttribute), false);
    var description = ((DescriptionAttribute)attributes[0]).Description;
    result.Add(description);
  }

  return result;
}

static void Main(string[] args)
{
  var x = DataFiat.Public | DataFiat.Listed;
  var y = x.GetAttribute<DataFiat>();

  var output = string.Join(" ", y.ToArray());
  Console.WriteLine(output);
}
}

I have changed the T to ICollection but you can change it as you wish or you can merege the data within the method and return the string back.

score -1 · Answer 5 · edited Sep 08 '14 at 21:29

I came up with a different solution based on my previous code. It can be used as follows:

  DataFiat fiat = DataFiat.Public | DataFiat.Listed;
  var b = fiat.ToString();
  var c = fiat.GetAttributes<TextAttribute>();

  var d = fiat.GetAttributes<TextAttribute, String>(x => String.Join(",", x.Select(y => y.Value)));

I think it becomes easy to use either to get the attributes or doing something with them.

What do you think?

Let me know if the code can be somehow improved. Here is the code:

public static List<T> GetAttributes<T>(this Enum value) where T : Attribute {

  List<T> attributes = new List<T>();

  IEnumerable<Enum> flags = Enum.GetValues(value.GetType()).Cast<Enum>().Where(value.HasFlag);

  if (flags != null) {

    foreach (Enum flag in flags) {
      MemberInfo info = flag.GetType().GetMember(flag.ToString()).FirstOrDefault();
      if (info != null)
        attributes.Add((T)info.GetCustomAttributes(typeof(T), false).FirstOrDefault());         
    }

    return attributes;

  }

  return null;

} // GetAttributes   

public static Expected GetAttributes<T, Expected>(this Enum value, Func<List<T>, Expected> expression) where T : Attribute {

  List<T> attributes = value.GetAttributes<T>();

  if (attributes == null)
    return default(Expected);

  return expression(attributes);

} // GetAttributes

Enum Description to String

5 Answers5